Process for preparing pyrazolecarboxylic acid compounds

ABSTRACT

There is disclosed a process for preparing a pyrazolecarboxylic acid derivative represented by the formula (II): ##STR1## wherein Y and Z each represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, COOR 1 , NR 1  R 2 , CONR 1  R 2 , SR 1 , SO 2  NR 1  R 2 , SO 2  R 3 , R 3  CO, OR 4 , CHX 2  or CX 3  ; A represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted pyridyl group or OR 5  ; where R 1  and R 2  each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; R 3  represents an alkyl group having 1 to 10 carbon atoms; R 4  represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group, CHF 2 , CF 3  or CF 3  CH 2  ; R 5  represents an alkyl group having 1 to 10 carbon atoms; and X represents a halogen atom, 
     which comprises oxidizing a pyrazole compound represented by the formula (I): ##STR2## wherein Y, Z and A have the same meanings as defined above, with an oxygen-containing gas in the presence of a metal compound catalyst.

BACKGROUND OF THE INVENTION

1. Field of The Invention

This invention relates to a novel method for preparingpyrazolecarboxylic acid derivatives which are useful as an intermediateof a herbicide, etc.

2. Background of The Invention

Heretofore, as the method for preparing pyrazolecarboxylic acid fromalkylpyrazole derivatives, it has been known the permanganic acidoxidation method.

However, this method uses excessive amount of permanganate and the yieldis extremely bad as 40% or lower.

Also, it is required to process a large amount of waste water and wastematerial containing manganese so that it is difficult to employ themethod as an industrial scale preparation.

Also, as the preparative method of heterocyclic carboxylic acid due tothe liquid phase autoxidation method, the following has been known.

(1) Japanese Patent publication No. 9868/1959

(2) Japanese Patent Publication No. 17068/1975

In the aforesaid (1), oxidation of a compound having pyridine orquinoline nucleus has been carried out in the presence of a heavy metalcompound such as manganese, cobalt, etc. and a bromine compound.

In the aforesaid (2), oxidation of alkylpyridine derivatives have beencarried out in the presence of a compound selected from zirconium,cobalt and manganese and a bromine compound to preparepyridinecarboxylic acids.

However, it has never been known the method in which only a methyl groupof a pyrazole compound having simultaneously a methyl group bonded tothe pyrazole ring and a substituent bonded to a nitrogen atom isselectively oxidized to give pyrazolecarboxylic acid derivatives.

SUMMARY OF THE INVENTION

The present inventors have intensively studied concerning the method ofobtaining a pyrazolecarboxylic acid derivative from a pyrazole compoundhaving simultaneously a methyl group bonded to the pyrazole ring and asubstituent bonded to a nitrogen atom, and as the result, accomplishedthe present invention.

That is, the present invention concerns a method for preparing apyrazolecarboxylic acid derivative represented by the formula (II):##STR3## wherein Y and Z each represent a hydrogen atom, a halogen atom,a nitro group, a cyano group, COOR₁, NR₁ R₂, CONR₁ R₂, SR₁, SO₂ NR₁ R₂,SO₂ R₃, R₃ CO, OR₄, CHX₂ or CX₃ ; A represents a hydrogen atom, an alkylgroup having 1 to 4 carbon atoms, a substituted or unsubstituted phenylgroup, a substituted or unsubstituted pyridyl group or OR₅ ; where R₁and R₂ each represent a hydrogen atom or an alkyl group having 1 to 10carbon atoms; R₃ represents an alkyl group having 1 to 10 carbon atoms;R₄ represents a hydrogen atom, an alkyl group having 1 to 10 carbonatoms, a substituted or unsubstituted phenyl group, CHF₂, CF₃ or CF₃ CH₂; R₅ represents an alkyl group having 1 to 10 carbon atoms; and Xrepresents a halogen atom,

which comprises oxidizing a pyrazole compound represented by the formula(I): ##STR4## wherein Y, Z and A have the same meanings as definedabove, with an oxygen-containing gas in the presence of a metal compoundcatalyst.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the above formula (II), as the halogen atoms for Y, Z and Z (that is,X in CHX₂ or CX₃), there may be mentioned a fluorine atom, a chlorineatom, a bromine atom and an iodine atom.

As the alkyl group having 1 to 10 carbon atoms for R₁, R₂, R₃, R₄ andR₅, there may be mentioned a methyl group, an ethyl group, a n-propylgroup, an i-propyl group, a n-butyl group, an i-butyl group, a t-butylgroup, a n-pentyl group, an i-pentyl group, a n-hexyl group, an i-hexylgroup, a n-heptyl group, an i-heptyl group, a n-octyl group, an i-octylgroup, a n-nonyl group, an i-nonyl group, a n-decyl group, an i-decylgroup, etc. Among these, as R₁ to R₅, a methyl group or an ethyl groupis particularly preferred.

As the alkyl group having 1 to 4 carbon atoms for A, there may bementioned a methyl group, an ethyl group, a n-propyl group, an i-propylgroup, a n-butyl group, an i-butyl group, a t-butyl group, etc. As A, amethyl group or an ethyl group is particularly preferred.

In the above, n means normal, i means iso and t means tertiary.

The substituents for the substituted or unsubstituted phenyl group andthe substituted or unsubstituted pyridyl group may include the abovementioned Y except for a hydrogen atom.

As the oxygen-containing gas, a pure oxygen gas or air may be used.

Oxygen partial pressure may be atmospheric pressure to 80 kg/cm²,preferably atmospheric pressure to 50 kg/cm².

As the metal compound catalyst, there may be mentioned aliphatic acidiron salts such as iron formate, iron acetate, iron lactate, ironoxalate, iron octylate, etc.; chelate compounds such as ironacetylacetonate, etc.; iron salts such as iron chloride, iron bromide,iron iodide, iron carbonate, iron sulfate, iron nitrate, etc.; aliphaticacid cobalt salts such as cobalt formate, cobalt acetate, cobaltoctylate, etc.; chelate compounds such as cobalt acetylacetonate, etc.;cobalt salts such as cobalt chloride, cobalt bromide, cobalt iodide,cobalt carbonate, etc.; aliphatic acid nickel salts such as nickelformate, nickel acetate, nickel octylate, etc.; chelate compounds suchas nickel acetylacetonate, etc.; nickel salts such as nickel chloride,nickel bromide, nickel iodide, nickel carbonate, etc.; aliphatic acidmanganese salts such as manganese formate, manganese acetate, manganeseoctylate, etc.; chelate compounds such as manganese acetylacetonate,etc.; manganese salts such as manganese chloride, manganese bromide,manganese iodide, manganese carbonate, etc.; aliphatic acid cerium saltssuch as cerium formate, cerium acetate, cerium octylate, etc.; chelatecompounds such as cerium acetylacetonate, etc.; cerium salts such ascerium chloride, cerium bromide, cerium iodide, cerium carbonate, etc.;aliphatic acid zirconium salts such as zirconium formate, zirconiumacetate, zirconium octylate, etc.; chelate compounds such as zirconiumacetylacetonate, etc.; zirconium salts such as zirconium chloride,zirconium bromide, zirconium iodide, zirconium carbonate, etc.; coppercompounds such as cupric acetate, cupric chloride, cupric carbonate,etc.; palladium compounds such as palladium acetate, palladium chloride,palladium iodide, etc.; osmium compounds such as osmium tetrachloride,etc.; and lead compounds such as lead tetraacetate, etc.

An amount of the metal compound catalyst is not particularly limited,but generally 0.1 to 20 gram-atom, preferably 1 to 10 gram-atom in termsof a metal based on 100 moles of the compound of the formula (I).

Also, the above metal compound catalysts may be used in combination, forexample, when 1 to 1/50 gram-atom, preferably 1 to 1/10 gram-atom ofmanganese is used to cobalt, good results can be obtained.

At least one of a bromine compound, a lithium compound or an alkalimetal salt of acetic acid may be used as a reaction promoter.

The bromine compound is not particularly limited and, for example, theremay be mentioned ammonium bromide, sodium bromide, potassium bromide,bromine, hydrogen bromide, etc. Sodium bromide or ammonium bromide isparticularly preferred. As the lithium compound, there may be mentionedlithium bromide, lithium chloride, lithium fluoride, etc., but lithiumchloride is particularly preferred. As the alkali metal salt of aceticacid, there may be mentioned sodium acetate, potassium acetate, lithiumacetate, etc., but potassium acetate is particularly preferred.

An amount of the bromine compound is not particularly limited, butgenerally 0.5 to 20 moles, preferably 1 to 10 moles based on 100 molesof the compound of the formula (I).

The reaction temperature is 20° to 200° C., preferably 60 to 180° C.

The reaction of the present invention may be possible without anysolvent but a solvent may be used.

If a solvent is used, operability, safety, and the like are improved.

The solvent is not particularly limited so long as it is stable, and mayinclude a lower aliphatic acid such as acetic acid, propionic acid, abutyric acid, etc.; a lower aliphatic acid anhydride such as aceticanhydride, propionic anhydride, etc., and acetic acid is particularlypreferred. An amount of the solvent is not particularly limited, but itis preferred to use 2-fold to 100-fold based on 1 part by weight of thesubstrate since good results can be obtained.

According to the present invention, the pyrazolecarboxylic acidrepresented by the formula (II) can be prepared from the pyrazolecompound represented by the formula (I) with ease and high yield.

Particularly, the present invention is effective as the method forpreparing 3,5-dichloro-1-methylpyrazole-4-carboxylic acid from3,5-dichloro-1,4-dimethylpyrazole.

The compound is an available compound as an intermediate of a herbicidefor corn field.

EXAMPLES

In the following, the present invention will be explained by referringto Examples, but the present invention is not limited by these.

EXAMPLE 1

In a 100 ml of an autoclave made of Hasteroy C-276 were charged 50 ml ofacetic acid, 8.25 g (50 mmole) of 3,5-dichloro-1,4-dimethylpyrazole,0.498 g (2 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganeseacetate and 0.408 g (4 mmole) of sodium bromide.

After supplying an oxygen gas in the autoclave to make 40 kg/cm², themixture was heated under stirring and reaction was carried out at 140°C. for 2 hours.

After the reaction, the products were taken out and analyzed by a gaschromatography, and as the result, a conversion ratio of the starting3,5-dichloro-1,4-dimethylpyrazole was 100%.

After removing acetic acid, the residue was esterified by dazomethaneand the products were analyzed by a gas chromatography-mass spectrographto obtain the result of M/e being 208 whereby it could be confirmed tobe a methyl ester of the objective compound.

As the result of the gas chromatography analysis, a yield of3,5-dichloro-1-methylpyrazole-4-carboxylic acid was 88.7%.

EXAMPLE 2

In the same manner as in Example 1 except for changing an oxygenpressure to 10 kg/cm², the reaction and operation were carried out.

A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was90.5% and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was79.9%.

Example 3

In the same manner as in Example 1 except for changing the reactiontemperature to 130° C., the reaction and operation were carried out.

A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was95.0% and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was85.0%.

EXAMPLE 4

In the same manner as in Example 1 except for charging 0.392 g (4 mmole)of ammonium bromide in place of sodium bromide, the reaction andoperation were carried out.

A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was100% and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was90.1%.

EXAMPLE 5

In the same manner as in Example 1 except for adding 7 mg (0.04 mmole)of ferrous oxalate as an iron compound, the reaction and operation werecarried out.

A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was95% and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was93%.

EXAMPLE 6

In a 100 ml of an autoclave made of titanium were charged 50 ml ofacetic acid, 6.5 g (50 mmole) of 5-chloro-1,4-dimethylpyrazole, 0.498 g(2 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganese acetateand 0.408 g (4 mmole) of sodium bromide, and after supplying air thereinto make 100 kg/cm2, reaction was carried at 140° C. for 2 hours. Aconversion ratio of the starting 5-chloro-1,4-dimethylpyrazole was 100%.After removing acetic acid, the residue was esterified by diazomethaneand the products were analyzed by a gas chromatography-mass spectrographto obtain the result of M/e being 174 whereby it could be confirmed tobe a methyl ester compound of the objective compound. As the result ofthe gas chromatography analysis, a yield of5-chloro-1-methylpyrazole-4-carboxylic acid was 86.2%.

EXAMPLE 7

In a 100 ml of an autoclave made of Hasteroy C-276 were charged 50 ml ofacetic acid, 4.8 g (50 mmole) of 1,4-dimethylpyrazole, 0.249 g (1 mmole)of cobalt acetate, 0.123 g (0.5 mmole) of manganese acetate and 0.204 g(2 mmole) of sodium bromide, and reaction and operation were carried outin the same manner as in Example 1.

A conversion ratio of the starting 1,4-dimethylpyrazole was 100% and ayield of 1-methylpyrazole-4-carboxylic acid was 87.7%.

EXAMPLE 8

In a 100 ml of an autoclave made of Hasteroy C-276 were charged 50 ml ofacetic acid, 9.6 g (50 mmole) of1-isopropyl-3-trifluoromethyl-5-methylpyrazole, 0.249 g (1 mmole) ofcobalt acetate, 0.123 g (0.5 mmole) of manganese acetate and 0.204 g (2mmole) of sodium bromide.

After supplying an oxygen gas in the autoclave to make 45 kg/cm², themixture was heated under stirring and reaction was carried out at 160°C. for 2 hours.

When the same operations were carried out as in Example 1, a conversionratio of the starting 1-isopropyl-3-trifluoromethyl-5-methylpyrazole was96.8% and a yield of 1-isopropyl-3-trifluoromethylpyrazole-5-carboxylicacid was 74.2%.

EXAMPLE 9

In a 100 ml of an autoclave made of Hasteroy C-276 were charged 50 ml ofacetic acid, 8.2 g (50 mmole) of 1,5-dimethyl-3-trifluoromethylpyrazole,0.249 g (1 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganeseacetate and 0.204 g (2 mmole) of sodium bromide, reaction and operationwere carried out in the same manner as in Example 1.

A conversion ratio of the starting1,5-dimethyl-3-trifluoromethylpyrazole was 96.8%, and a yield of1-methyl-3-trifluoromethylpyrazole-5-carboxylic acid was 52.0%.

EXAMPLE 10

In a 100 ml of an autoclave made of Hasteroy C-276 were charged 50 ml ofacetic acid, 10.5 g (50 mmole) of3-chloro-1,4-dimethylpyrazole-5-sulfonamide, 0.249 g (1 mmole) of cobaltacetate, 0.0615 g (0.25 mmole) of manganese acetate and 0.204 g (2mmole) of sodium bromide, reaction and operation were carried out in thesame manner as in Example 1.

A conversion ratio of the starting3-chloro-1,4-dimethylpyrazole-5-sulfonamide was 90%, and a yield of3-chloro1-methyl-5-sulfonamidopyrazole-4-carboxylic acid was 75.5%.

EXAMPLE 11

In a 100 ml of an autoclave made of Hasteroy C-276 were charged 50 ml ofacetic acid, 10.3 g (50 mmole) of5-tertiarybutylthio-3-chloro-1,4-dimethylpyrazole, 0.249 g (1 mmole) ofcobalt acetate, 0.0615 g (0.25 mmole) of manganese acetate and 0.204 g(2 mmole) of sodium bromide, reaction and operation were carried out inthe same manner as in Example 1.

A conversion ratio of the starting5-tertiarybutylthio-3-chloro-1,4-dimethylpyrazole was 74.5%, and a yieldof 5-tertiarybutylthio-3-chloro-1-methylpyrazole-4-carboxylic acid was52.2%.

We claim:
 1. A process for preparing a pyrazolecarboxylic acid compoundrepresented by the formula (II): ##STR5## wherein Y and Z each representa hydrogen atom, a halogen atom, a nitro group, a cyano group, COOR₁,NR₁ R₂, CONR₁ R₂, SR₁, SO₂ NR₁ R₂, SO₂ R₃, R₃ CO, OR₄, CHX₂ or CX₃ ; Arepresents a methyl group; where R₁ and R₂ each represent a hydrogenatom or an alkyl group having 1 to 10 carbon atoms; R₃ represents analkyl group having 1 to 10 carbon atoms; R₄ represents a hydrogen atom,an alkyl group having 1 to 10 carbon atoms, a substituted orunsubstituted phenyl group, CHF₂, CF₂ or CF₃ CH₂ ; and X represents ahalogen atom which comprises oxidizing a pyrazole compound representedby the formula (I): ##STR6## wherein Y, Z and A have the same meaningsas defined above, by contacting said compound of the formula (I) with anoxygen-containing gas in the presence of a metal compound catalyst, at atemperature of 20° to 200° C. the partial pressure of saidoxygen-containing gas being from atmospheric pressure to 80 kg/cm² andthe said metal compound catalyst is in an amount of 0.1 to 20 gram-atombased on 100 moles of the compound of the formula (I) and is at leastone compound selected from the group consisting of iron compounds,cobalt compounds, nickel compounds, manganese compounds, ceriumcompounds and zirconium compounds.
 2. The process for preparing apyrazolecarboxylic acid compound according to claim 1, wherein said Yand Z are both chlorine atoms.
 3. The process for preparing apyrazolecarboxylic acid compound according to claim 1, wherein saidoxygen-containing gas is pure oxygen gas or air.
 4. The process forpreparing a pyrazolecarboxylic acid compound according to claim 3,wherein the partial pressure of the oxygen-containing gas is fromatmospheric pressure to 50 kg/cm².
 5. The process for preparing apyrazolecarboxylic acid compound according to claim 1, wherein saidmetal compound catalyst is at least one selected from the groupconsisting of cobalt compounds, manganese compounds and iron compounds.6. The process for preparing a pyrazolecarboxylic acid compoundaccording to claim 5, wherein said metal compound catalyst is (i) atleast one cobalt compound and (i) at least one manganese compound whichare selected from the group consisting of aliphatic acid cobalt salts,chelate compounds of cobalt, cobalt salts, aliphatic acid manganesesalts, chelate compounds of manganese and manganese salts.
 7. Theprocess for preparing a pyrazolecarboxylic acid compound according toclaim 6, wherein said cobalt compound and the manganese compound areselected from the group consisting of cobalt formate, cobalt acetate,cobalt octylate, cobalt acetylacetonate, cobalt chloride, cobaltbromide, cobalt iodide, cobalt carbonate, manganese formate, manganeseacetate, manganese octylate, manganese acetylacetonate, manganesechloride, manganese bromide, manganese iodide and manganese carbonate.8. The process for preparing a pyrazolecarboxylic acid compoundaccording to claim 7, wherein said metal compound catalysts are cobaltacetate and manganese acetate.
 9. The process for preparing apyrazolecarboxylic acid compound according to claim 7, wherein theamount of manganese of said manganese compound to cobalt of said cobaltcompound is 1 to 1/50 gram-atom.
 10. The process for preparing apyrazolecarboxylic acid compound according to claim 1, wherein a brominecompound is further added in the reaction system as a reaction promoter.11. The process for preparing a pyrazolecarboxylic acid compoundaccording to claim 10, wherein said bromine compound is selected fromthe group consisting of ammonium bromide, sodium bromide, potassiumbromide, bromine and hydrobromide.
 12. The process for preparing apyrazolecarboxylic acid compound according to claim 11, wherein saidbromine compound is sodium bromide.
 13. The process for preparing apyrazolecarboxylic acid compound according to claim 12, wherein theamount of said bromine compound is 0.5 to 20 moles based on 100 moles ofthe compound of the formula (I).
 14. The process for preparing apyrazolecarboxylic acid compound according to claim 1, wherein thereaction is carried out in the presence of a solvent.
 15. The processfor preparing a pyrazolecarboxylic acid compound according to claim 14,wherein the solvent is selected form the group consisting of a loweraliphatic acid or a lower aliphatic acid anhydride.
 16. The process forpreparing a pyrazolecarboxylic acid compound according to claim 15,wherein the solvent is selected from the group consisting of aceticacid, propionic acid, butyric acid, acetic anhydride and propionicanhydride.
 17. The process for preparing a pyrazolecarboxylic acidcompound according to claim 16, wherein the solvent is acetic acid. 18.The process for preparing a pyrazolecarboxylic acid compound accordingto claim 1, wherein the compound of the formula (I) is selected from thegroup consisting of 3,5-dichloro-1,4-dimethylpyrazole,5-chloro-1,4-dimethylpyrazole, 1,4-dimethylpyrazole,1,5-dimethyl-3-trifluoromethylpyrazole,3-chloro-1,4-dimethylpyrazole-5-sulfonamide and5-tertiarybutylthio-3-chloro-1,4-dimethylpyrazole.
 19. The process forpreparing a pyrazolecarboxylic acid compound according to claim 3,wherein the partial pressure of the oxygen-containing gas is fromatmospheric pressure to 50 kg/cm² ; said metal compound catalyst is atleast one cobalt compound, and one manganese compound and the amount ofmanganese of said manganese compound to cobalt of said cobalt compoundif 1 to 1/50 gram-atom; a bromine compound is further added in thereaction system as a reaction promoter and the amount of said brominecompound is 0.5 to 20 moles based on 100 moles of the compound of theformula (I) and the reaction is carried out in the presence of asolvent.
 20. The process for preparing a pyrazolecarboxylic acidcompound according to claim 19, wherein said cobalt compound and themanganese compound are selected from the group consisting of cobaltformate, cobalt acetate, cobalt octylate, cobalt acetylacetonate, cobaltchloride, cobalt bromide, cobalt iodide, cobalt carbonate, manganeseformate, manganese acetate, manganese octylate, manganeseacetylacetonate, manganese chloride, manganese bromide, manganese iodideand manganese carbonate; said bromine compound is selected from thegroup consisting of ammonium bromide, sodium bromide, potassium bromide,bromine and hydrobromide; the solvent is selected from the groupconsisting of acetic acid, propionic acid, butyric acid, aceticanhydride and propionic anhydride; the amount of said metal compoundcatalyst is 1 to 10 gram-atom based on 100 moles of the compound of theformula (I) and the amount of manganese of said manganese compound tocobalt of said cobalt compound is 1 to 1.10 gram-atom.
 21. The processfor preparing a pyrazolecarboxylic acid compound according to claim 20,wherein said Y and Z are both chlorine atoms; said metal compoundcatalysts are cobalt acetate and manganese acetate; said brominecompound is sodium bromide and the solvent is acetic acid.
 22. Theprocess for preparing a pyrazolecarboxylic acid compound according toclaim 21, wherein the compound of the formula (I) is selected from thegroup consisting of 3,5-dichloro-1,4-dimethylpyrazole,5-chloro-1,4-dimethylpyrazole, 1,4-dimethylpyrazole,1,5-dimethyl-3-trifluoromethylpyrazole,3-chloro-1,4-dimethylpyrazole-5-sulfonamide and5-tertiarybutylthio-3-chloro-1,4-dimethylpyrazole.
 23. The process forpreparing a pyrazolecarboxylic acid compound according to claim 20,wherein the compound of the formula (I) is3,5-dichloro-1,4-dimethylpyrazole.